Impact of Sewage on Seed Germination and Early Growth of Amaranthus: A Phytotoxicity Study

Aims: To investigate the phytotoxic effects of sewage on the germination of red amaranthus as a preliminary step before field trials. Study Design: Completely Randomized Design (CRD) with four replications. Place and Duration of Study: Department of soils and environment, Agricultural college and research institute, Madurai. During April – June, 2024. Methodology: The experiment utilized six treatment levels - control, 20%, 40%, 60%, 80%, and 100% raw sewage - employing a Completely Randomized Design (CRD) with four replications. The experimental data were collected and analyzed. Results: The results showed that the physico-chemical parameters such as electrical conductivity (EC) and total dissolved solids (TDS) were relatively high in the sewage, causing toxicity to plant, severely affected seed germination and early seedling growth. The maximum toxicity (85-100%) was recorded at 100% sewage concentration, while the minimum relative toxicity percentage (1.5-3.1%) was observed at a 20% sewage. The highest phytotoxicity (100%) occurred at 7 days after sowing (DAS) in the 100% effluent. Conclusion: The dilution with lower EC and TDS had the less adverse effect on the growth of roots and shoots as compared with the higher concentrations. This study indicates that raw sewage wastewater could be harmful, but diluting it may allow it to be safely used for irrigating amaranthus.